Fluid pressure brake mechanism



June 28, 1960 J. o. EAMES 2,942,699

FLUID PRESSURE BRAKE MECHANISM Original Filed June 11, 1956 4Sheets-Sheet 1 INVENTOR JA MEJ 5/: M56

BY Jazz/21mm? ATTORNEYS June 28, 1960 I J. o. EAMES FLUID PRESSURE BRAKEMECHANISM Original Filed June 11, 1956 4 Sheets-Sheet 2 INVENTOR JAMESO. fAMas BY 9 ATTORNEYS June 28, 1960 J. o. EAMES FLUID PRESSURE BRAKEMECHANISM Original Filed June 11, 1956 4 Sheets-Sheet 3 c/AMfiS 0. EAMESATTORNEYS Jun; 28, 1 960 J. O. EAMES FLUID PRESSURE BRAKE MECHANISMOriginal Filed June 11, 1956 4 Sheets-Sheet 4 INVENT OR L/AMEG O. EAMEJJW u ATTORNEYS United States Patent FLUID PRESSURE BRAKE James 0. Eames,Washington, Conn., assignor to Roy S. Sanford, Woodbury, Roger H. Caslerand James 0. Eames, Washington, and Wilfred A. Eaton and Erling D.Sedergren, Woodbury, Conn.

Continuation of abandoned application Ser. No. 590,618 June 11, 1956.This application Sept. 23, 1957, Ser. No. 686,271

16 Claims. (Cl. 188-264) This invention relates to frictional mechanism,and more particularly to friction brake mechanism of the type whereinfriction elements are utilized which are cooled by a circulating liquidunder pressure, and wherein fluid pressure responsive means are providedfor effecting engagement of the friction elements.

More particularly, this invention relates in general to brake mechanismsof the type set forth in the co-pending' application of Roy S. Sanfordand James O. Eames, Serial Number 475,072, filed in the United StatesPatent Office on Dec. 14, 1954, now Pat. No. 2,821,273. The presentinvention includes improvements over the mechanisms set forth in theabove application, and'one of the objects of the invention is to providea simplified form of brake mechanism requiring a minumum number ofparts.

As set forth in the above referred to application, metallic frictionelements are provided which preferably are adapted to engage rotatingfriction discs or rings of relatively non-heat conductive compositionmaterial, the entire surfaces of the metallic friction elements directlyopposite the surfaces in engagement with the friction rings being cooledby the action of a circulating liquid, and supported against mechanicaldistortion by the pressure of that liquid, the areas of the actuatingmeans for the friction elements and the areas of the engaging portionsof the friction elements and the portions supported by the pressure ofthe liquid being so chosen as to obtain a balance of forces in bothdirections on the metallic friction elements which engage the frictionrings during a brake application.

In a disc brake having two metallic friction elements and twocomposition friction rings engageabletherewith,

the use of two pressure responsive elements has previously been requiredto effect frictional engagement of the elements, and it is one of the obects of the invention to accomplish the above result with the use of asingle pressure responsive element, or in the case where four metallicfriction rings and composition friction rings are utilized, for example,to accomplish the desired result with the use of only two pressureresponsive members or pistons.

A further object of the invention is to provide means for supporting allof'the metallic friction elementsin the brake against distortion due totheir mechanical engagement with the rotating composition frictionrings'of the brake; v

Still another object of the invention is to provide a brake mechanism ofthe above type wherein the number of moving parts utilized is reduced toa Another object of the invention is to provide, in a brake of the abovetype, means for efiectively separating the engaging friction elements onrelease of the brake in order to prevent dragging of the brakes.

A further object is the provision of novel means for directing the flowof circulating liquid through the brake mechanism in an efficient and.simple manner.

Yet another'object of the invention is to provide a con Patented June28, 1960 "ice struction wherein the inlet and outlet conduits forcooling liquid; leading to and from the brake mechanism may be readilyconnected thereto without interference with other parts of the vehicle.v

Still another object of the invention is to provide means forautomatically compensating for wear of the friction elements of thebrake.

Another object is the provision of means for directing theflowofcooling'liquid through the brake to efl'ect substantially uniformcooling of the friction elements of the brake.

The above and other objects and novel features of the invention will bemore fully understood when considered in the light of the followingdescription and the accompanying drawings. It is to be specificallyunderstood, however, that the drawings are utilized for purposes ofillustration only, reference being bad to the appended 'claimsfor adefinition of the limits of the invention.

In the drawings, wherein similar reference characters are utilized toidentify similar parts throughout the several views:

Fig. 1 shows a s'ectional view of a hydraulically operated and liquidcooled brake mechanism constructed in accordance with the principles ofthe present invention, the section being taken along line 1--1 of Fig.2;

Fig. 2-isan end view of the brakeof Fig. 1 taken from the right with theouter housing removed;

Fig. 3'is a sectional view taken along line 3-3 of Fig. 2;

Fig. 4 is a plan view of the brake looking outward along the axle of thevehicle; V

Fig. 5 is a sectional view takenalong lines 5-5 of Fig. 4;

Fig.6 is a diagrammatic view, partially in section of a ,controlsystemfor circulating cooling liquid through the brake actuator andcontrolling the pressure of said liquid therein;

Fig. 7 is a sectional view of a multiple disc brake constructed inaccordance with the principles of the invention; and

Fig. 8 is a" partial sectional view of Fig. 7, taken at 99 to theshowing of that figure.

Referring first to Fig. l of'the drawings, the brake mechanism includesa hub 10 rotatably mounted onan axle 11 and having 'a flange 12 asshown. A brake cylinder memberlS is suitably secured to the vehicle axleagainst rotation, and a friction element supporting member 14 is securedthereto as by means of bolts or cap screws' 15. A rotatable brake member16 is secu'red'to the flange 12 for rotation therewith by meansofs'tu'ds 17, and an" annular member 18 is secured thereto by means ofcap screws 19. A metallic lining disc 20 is provided around itsperiphery with bores 21 in slidable engagement with the cap screws 19,so that the lining disc rotates with the hub and with the members 16 and18, composition friction rings 22 being'secured to either side of thelining disc as shown for rotation therewith. A metallic ring rnember'23i's-secured to the outer periphery of the disc 20 by means of welding orotherwise, and serves in conne'ction'with the faceof the disc,.toprovide a groove2'4 along the outer'periphery of the lining plate. Aresilient member or 0" ring 25 of rubber-like material is disposed insaid groove, being under compression between the bottom of thegroove'a'nd the inner surface of the member 18, and in slidableengagement with the latter surface, for purposes to be more" fullydescribed hereinafter; may be disposed under compression between otherportions of the lining'idisc and drum in sliding engagement with oneandmovable bodily with the other, if desired- An annular channel 26 isformed in the stationary As will be explained later, the resilientmember These pins of course permit sliding movement of the pistonthereon during a brake application, and at the same time preventrotation of the piston in its cylinder due to the braking torque.

The above described, arrangement of the cooling liquid passages and theplenum chambers is advantageous in providing for the positioning of theinlet and outlet ports 36 and 46a above the vehicle axle, thus servingto provide adequate protection for the conduits leading to these ports.Itwill be apparent, that in the event one or both of these conduits wereconnected to the brake below the axle, they might be subject to damageonv certain types of highways. With the arrangement shown, however, theports and conduits are located above the axle.

Although in the construction shown in Fig. 1, only one piston orpressure responsive member is utilized to effect engagement of twometallic friction elements with corresponding composition frictionrings, the arrangement is such that the metallic friction elements aresupported against distortion in either direction in the same manner asset forth in the above referred to application of Sanford and Eames. Theforce serving to e'nect engagement between the metallic friction element41 and the left composition ring 22 of Fig. 1, as well as the forceeffective to engage metallic friction element 29 with the othercomposition friction ring 22, is determined by the area of the piston.This area is substantially the same as that of the friction elementareas bounded by the peripheral portions thereof and the areas of eachof the friction rings 2-2. Since the channels 25 and 40 are subjected tothe pressure of the circulating cooling liquid which acts to move thepiston during a brake application, the pressure of cooling liquid inchannels 26 and 40 is substantially the same as that acting on thepiston, and the pressure in these channels serves to support thoseportions of the metallic friction elements which are exposed in thechannels and which are unsupported directly either by the member 14 orby the piston. The remaining peripheral portions of the metallicfriction elements which bound the annular areas which engage thecomposition friction rings 22 are supported against distortion by virtueof their attachment to the member 14 or to the piston by means of therivets shown. Consequently the total force tending to effect engagementbetween the unsupported portions of the metallic friction elements inone direction supplied by the piston, is balanced by the pressureexerted on the metallic friction elements in the channels 26 and 40, andduring engagement, the said annular friction area portions of theelements are prevented from bulging outwardly by virtue of theirengagement with the surfaces of the composition friction rings. Thus,the construction is such that the metallic friction elements 29 and 41may be made relatively thin and flexible, as well as of metals whichlack structural strength and resilience, such as copper. It should benoted in this connection, that copper has been found to be anoutstanding material for the metallic friction elements in a brake ofthis type, wherein means are provided for supporting such elementsagainst distortion in either direction, which is necessary in connectionwith a relatively soft and ductile metal such as copper. The broadaspect of the situation is that the metallic friction elements aresupported against distortion in either direction during a brakeapplication, either by the supporting member 14 and piston 33, by the.pressure of cooling liquid behind the metallic friction elements, or byengagement of the elements with the rotating composition friction rings22. The relationships need not of course be exact, since the metallicfriction elements, even though thin and flexible, have some strength oftheir own which may be relied upon to take care of discrepancies in theforce-balance relationships.

Means are also provided for automatically retracting the piston onrelease of pressure therefrom, as well as for retracting the disc 20' inorder to prevent dragging of the brakes. The rings 43 and 44- serve, asset forth in the above referred to Sanford and Eames application,

to not only retract the piston on release of pressure from the cylinder32, but also to automatically adjust the position of the piston and themetallic friction element 41 in accordance with wear of the brakingsurfaces. It will be noted that the O ring is positioned in grooves inthe cylinder walls, and that consequently the 0 rings tend to bedistorted to the right with the movement of thev piston when subjectedto the action-of pressure of liquid. in the cylinder. On release of thepressure, the 0 rings tend to return to their undistorted positions, andin view of their frictional engagement with. the walls of the piston,tend to return the latter to the. left in order to prevent dragging ofthe brakes. As wear of the braking surfaces occurs, the piston may slideto the right through the 0 rings, and on release. of pressure, thepiston will be returned to a new release position by the action of theresilient 0 rings. The O ring 25 on the lining plate 20 is not Subjectedto liquid pressure, but is in slidable engagement with the inner surfaceof the member 18, and on movement of the plate to the right during abrake application, the 0 ring is distorted to the left relative to thegroove 24 by virtue of its frictional engagement with the inner wall ofthe member 18, and consequently, on release of pressure from thecylinder 32, the plate 26 will be moved to the left by the 0 ring .soonas the piston is moved to the left by the operation of the 0 rings 43and 44. It will be noted that in the embodiment of the invention shownin Fig. l, the 0 rings 43 and 44 are of somewhat larger cross-sectionthan the O ring 25. Consequently they are subject to greater distortionduring the brake application, and tend. to return the piston through agreater distance than that through which the plate 20 is returned by thereturn of the O ring 25 to its normal undistorted position. Thisarrangement accordingly provides for clearance not only between themetal ic friction element 29 and its adjacent composition friction ring22, but also between the metallic friction element 41 and its adjacentfriction ring 22. It will be apparent from the foregoing, that onrelease of liquid pressure from the brake mechanism, the retractingmovement of the piston should be greater than that of the friction plate29 in order to insure against dragging of the brake between either ofthe metallic friction elements and their adjacent composition frictionrings, and the 0 rings on the piston and on the lining disc 20 may be soproportioned as to accomplish this desirable end. Although the 0 ring 25is shown as being mounted in a groove on the periphery of the plate 20,it will be clearly understood that one or more 0 rings may be installedunder compression between other portions of the plate 20 and of themember 18 in such a manner as to perform the same function. Thus, noseparate return springs are required for the piston, and the brakealways remains in adjustment, with the piston being retractedsufficiently following each brake application to prevent any dragging ofthe brake, while compensating at all times for wear of the frictionelements. In the latter connection, it will be noted that the O ring 25also acts as an automatic slack adjuster for the plate 20, since onmovement of the plate to the right, the ring will first distort anamount determined by its crosssectional dimension and by the dimensionsof the groove 24, and will thereafter silde on the inner surface of themember 18, this sliding normally occurring only in the event of wear ofthe metallic friction element 29 and its adjacent composition frictionring. The plate will be returned to the left, however, following a brakeapplication, only by the amount of distortion of the O ring prior tosliding movement of the latter in the member 18, and

consequently a substantially predetermined clearance will be maintainedbetween the metallic friction element 29 and the adjacent compositionfriction ring 22 when the brake is in release position. 7

Although various systems may be utilized to control the flow of coolingliquid to and from the brake mechanism and to control the pressure ofthe liquid therein to effect a controlled application of the brake, onesuch system is shown in Fig. 6 'of the drawings, wherein a {pump 65,preferably of the positive displacement type, is driven by a' vehicle'engine '66. A radiator or heat exchanger 67 is associated withthe'eng'ine, and provided with alower tank 68 connected the inlet of thepump :by a conduit 69, and an upper tank 70,connected with the upperportion of the engine water jacket through a conduit 71. The outlet ofthe pump is connected to an inlet port 72 of a control valve mechanism73 by a conduit 74, and an outlet port 75 of the control valve isconnected tothe lower portion of the engine water jacket by means of aconduit 76.

The control valve is provided witha housing 77 having a bore 78the'rein, and having a valve spool 79 slidably mounted therein. Thevalve spool is provided with'a groove 80, :which with the spool valve inretracted position as shown in Fig. 6, serves to connect the ports 72 1The control valve housing is also provided with a brake I supply port 85and a brake returnport 8 6, the supply 'portlbeing connected to theinletport 36 of the brake v by a conduit 87, and the return port 86 beingconnected to the outlet 'port 46a ofthefbrake by a conduit 88.

The valve spool 79 is provided with a land '89fat the left of the groove80, and a second land 90 at the right of the groove, the land 90 beingso positioned as to normally prevent communication between the groove 80and the brake supply port 85. A vent port 91 is also provided in thewall of the bore'78, and is adapted to be closed off on initial movementof the valve spool 79' to the right of the position shown. This port isconnected with the upper tank of the radiator by a conduit 92, and theupper tank isvented to atmosphere by means of a conduit 93. In additionto the foregoing, the valve spool is provided with a bore 94 open at itsleft end, and

connected at the right end with the bore 78 by means of a port 95. Theright end of the valve spool is provided with a tapered valve portion 96adapted to engage a valve seat 97 formed on a member 98- secured to thevalve housing in the right end of the bore78 and carrying the return.port 86 to which the conduit 88 is connected;

From the foregoing, it will be seen that when the vehicle engine isoperating, the cooling liquid from the radiator is'normally circulatedthrough the pump and through the control valve .and back to the uppertank in the radiator as heretofore stated, circulation of the liquidthrough the'brake mechanism being prevented bythe land90' on the valvespool. In the event it is desired 1 to apply the brake, the pedal 83 ismoved to'the right,

whereupon the valve spool starts to restrict the connection between theports 72 and'75 and to open the connection between the groove 80 and thebrake supply port 85, at the. same time closing on, the vent port 91leading spool moves to the right, a' portion of the circulating liquid.is 'directedito the brake supply port 85 and the ,nels '26and 4'9ofijthe brake as heretofore described. The

liquid which returns from thefbrake is returned to the conduit 87, andis returned to-Jthe bore 78 of the control valve mechanism through theconduit 88 and the return port 86, the liquid circulating through thecooling chanlower'portionof-the engine'water jacket and thence totheright, the flow of water to the brake is increased, and

this-together with the progressive closing of the valve portion 96toward the seat 97, increases'the prcssureof theliquid in the brake, dueto the increased flow of liquid as well as to the restriction imposed onthe return of the liquid from the brake by the closing of the taperedvalve portion 96.

Y From the above, it will 'be apparent that means are provided forutilizingthc cooling system of the vehicle engine to provide for thecirculation of cooling liquid 1 through the brake mechanism and forcontrolling the brake application dependent upon'the position or thebrake pedal. It should be noted that regardless of Whether the brake isapplied or released, all the liquid pumped by the pump ,65 circulates atall times through the engine radiator, but only circulates through thebrake when the brake pedal is depressed. Although one type of system hasbeen shown for operating the brake, it Will-be understood that the pumpmay be driven by other means than the vehicle engine, and, that i-fdesired, the heat exchanger utilized inconne'ction with the brake systemmay be separate from the vehicleradiatonand that the brake liquidcirculating system may be entirely divorced from the desired.

.7 and'8.

' to the upper tank of the radiator. Thus, as the valve Although thebrake mechanism illustrated in Fig. l is shown as having two metallicfriction elementspand two rotating composition friction elements, it.will be understood that additional friction elements may be re: quiredin some cases in order to obtain a greater fric tion area, and this maybe done as illustrated in Figs. Referring'first to Fig. 7, a brake isshown having four metallic friction elements and tour rotatingcomposition friction rings in order to obtain an increased friction areain a given overall brake diameter, The mechanism includes a drum 16rotatably mounted on an axle 11 and having an annular member 18 securedto the left end of the drum for rotation therewith by means of capscrews 19. A pair of annular lining discs 20 are slidably mounted on thecapscrews v19 for axial movement therealong and for rotation with thedrum, each of the plates having composition friction rings 22 mounted oneither side thereof for rotation therewith. -A cylinder member 13 issecured to the axle, and a member 1415 secured to the member13 by capscrews15w-itli an intermediate friction element supporting member 99clamped therebetween as shown. The construction of the member .13 issubstantially the samelas that :of the memberlB shown in Fig; 1, themember" having a cylinder 32 formed therein and a rigid piston 33slidably mounted therein the passage 102 connects with ,an annularcylinder 105 formed in'the member 14, by means. of iaport 106.

The channels" 103a and 104 in the intermediate member theradiatorthrough the port in the spool valve, the

bore '94,L and past the lefit endof the land 89 to the valve return port75, and thence through conduit 76, the engine water.jacket',-'and theconduit 71 leading to'the upper tankot the radiator. Thus, as the'spoolvalve moves to 99 are open respectively at their left and right ends,and are closed by metallic friction elements 107 and 108 secured tothemember. .The cylinder. in the mem ber 14 has a rigid piston 109mountedtherein and having the same construction as' the piston in thelefthand cylinder, the piston being provided with a'partition 110 con:

vehicle enginecirc'ulating system if iiecting the inner and outer end bymeans of a metallic friction element 112 secured tothe left end of thepiston. Consequently, when the pistons are subjected to liquid underpressure, as will be more fully described hereinafter, the left handpiston in the cylinder 32 moves to the right to effect engagement of themetallic friction element thereon with the left hand compositionfriction ring 22 on the left hand disc 20, and the disc is moved to theright to effect engagement of the right hand composition friction ringthereon with the metallic friction element 167 on the intermediatemember 99. At the same time, the right hand piston -9 is moved to theleft to effect engagement between the metallic friction element 112 andthe right hand composition friction ring 22 on the right hand disc 20,and this disc is moved to the left to effect engagement of the left handcomposition friction ring thereon with the metallic friction element 198which is secured to the intermediate member 99.

The flow of cooling liquid in this particular embodiment of the brakemechanism will now' be described. The cooling liquid enters the brakethrough the inlet port 36 and flows into the passages 16!) and 101 and162. 'From the passage 1130, the liquid flows into the cylinder 32through a port 103 in the member 13, and thence into the channel 40 inthe piston through a port 113 in the partition 39 of the piston. Fromthis port, it flows circumferentially through the piston channel 40 inboth a clockwise and counterclockwise direction to the upper end of thechannel, and is discharged from the channel through a tube or dam 114secured to the partition 39 at one end, and having the other endslidably mounted in a bore 115 in the back wall of the cylinder 32 asshown. The left end of this tube communicates with an outlet passage 116in the member 13, and this, pas.- sage in turn is connected to theoutlet port 465. The passage 116 communicates with the channels 193a and104 in intermediate member 99 through a passage 117 therein, which inturn is connected with a passage 118 in the member 14. Thus, with regardto the left side of the brake, the liquid enters through the port 36,and reaches the outlet port 46:! of the brake through the passage 109,the port 103, the port 113 in the piston partition, the piston channel411, the tubular member or darn 114, and the passage 116. The liquid isprevented from flowing directly from the inlet port to the outlet portthrough the annular cylinder by' the tubulardam member 114, andconsequently the cylinder 32 forms a static pressure chamber subjectedto the pressure of the circulating liquid, While the channel 40 in thepiston is a liquid circulating chamber which maintains a supply ofcircuiating liquid in intimate contact with the inner surface of themetallic friction element 41.

Referring now to the flow of cooling-liquid through the channels 1113aand 104, liquid is supplied to the channels from the passage 1%,through'the passage 161 and a passage 119, and flows circumferentiallythrough the annular channels 103a and 1114 in both directions to theupper part of the member 99. It is discharged from the channels into thepassage 117 through a passage 120, and is discharged from the brakethrough the passage 116 and the outlet port 46a. It will be noted thatthe channels 103a and 194 in the member 99 are separated by means of apartition 121, except where the passages 119 and 12% enter the channels.

Referring now to the right hand pontion of the brake, and to the flow ofliquid to the channel 111 of the piston 1119, fluid flows from thepassage 102 in the member 14 to the cylinder 105 through port 105 in themember, as heretofore described, and thence into the channel 111 behindthe metallic friction element 112 through a port 122 in the partition110. From this point, the liquid flows upward around the channel in botha clockwise 10 and. counterclockwise. direction to the upper portion ofthev channel, and flows from there into the passage 118 in the member 14through a tubular dam member 123 secured at its left hand to the pistonpartition and slidably mounted at its right end in a bore 124 in member14. Having reached the passage 118, the liquid flows to the outlet port46a through the passages 117 and 116.

\It will be noted from the foregoing, that the inlet passages 100, 101,and 102, form in conjunction with each other an inlet plenum chamber 125which receives circulating liquid from the inlet port 36 and serves todistribute the liquid uniformly to the various channels through themeans already described. In like manner, the passages 116, 117, and 113form an outlet plenum chamber 126 which receives liquid from the variouscooling liquid channels and discharges it from the brake through theport 46a.

Anchor pins are provided in a manner similar to that shown in Fig. l,and referring to Fig, 8, it will be seen that anchor, pins 69 aresecured to members 13 and 14,

mounted in bores 64 formed in the partitions 39 and 110 .of the left andright hand pistons respectively. Additional anchor pins of the sameconstruction are preferably spaced apart from the anchor pins shown inFig; 8, and serve effectively to prevent rotation of the pistons intheir cylinders when the brake is applied. Thepistons are provided withinner and outer 0 rings 43 and 44 as shown in Fig. 1, while the liningdiscs 29 are provided with 0 rings 25 at their peripheries. Asheretofore described in connection with Fig. 1, these 0 rings tend tonot only retract the piston and the lining disc on release of thebrakes, but also act to automatically adjust the positions of thepistons and the lining discs to compensate for any wear which occurs onthe friction elements of the brake. Thus the 0 rings, as set forth inconnection with Fig. .1, provide an automatic brake slack ad juster andautomatic retracting means without the need for any additional mechanismbeing utilized.

The area relationships of the pistons and the annular friction areaportions of the metal friction elements, as well-as the areas of thefriction rings 22, are preferably substantially the same as set forth inconnection with Fig. '1 in order to obtain the desired balance of forcesin opposite directions on the metallic friction elements to preventdistortion thereof in either direction during a brake application, theconstruction being such that these friction elements are substantiallyso supported either by fluid pressure, the brake structure, or by thecomposition friction rings, as to substantially prevent any distortionof the metallic friction elements during a brake application. Inaddition to the foregoing, the mechanical forces exerted by the pistonsin either direction may be so balanced that there is no tendency todistort the intermediate member 99 in either direction with relation tothe members 13 and 14.

It will thus be seen, that in the structure of Figs. 7 and 8, novelbrake mechanism has been provided so constituted as to incorporate theprinciple of balancing the forces across the metallic friction elements,as set forth in the above referred to Sanford and Eames application,while at the same time, only requiring two pistons for the engagement offour metallic friction elements with four composition friction ringsurfaces. Although one arrangement of this type is shown in the abovereferred to figures, it will be readily apparent to those skilled in theart that other arrangements may be utilized in such a manner as toobtain proper operation of the brake mechanism utilizing one piston'orpressure responsive member for the engagement of each pair of metallicfriction elements with each pair of composition friction rings. H

It will be'evident from the foregoing specification, t at novel andefficient brake mechanism has been provided; wherein the number ofpressure responsive elements or 'lating system. 7 ing means and slackadjusting means are also-provided as pistons required is materiallyreduced, and wherein thin and flexible metallic friction elements may beutilized having an area on one surface adapted to engage compositionfriction rings and a corresponding area directlyopposite theretounsupported by the brake structure and sup- 7 ported only by thepressure of the cooling liquid in engagement therewith. In addition,substantially the entire area directly opposite the friction area isexposed directly to the'action ofthe cooling liquid, thus resulting inrapid transfer of the heat of friction to the cooling liquid and thenceto the heat exchanger of the cooling liquid circu- Novel automaticfriction'element retractheretofore described without the requirement foradditional parts for the performance of these desirable functions.

. Although the invention has been illustrated and deabandoned; for FluidPressure Brake Mechanism.

What is claimed is:" a a 7 1;. Liquid cooled and liquid pressureoperated brake a mechanism .including'a support, a brake member mountedfor rotation on the support, abrake disc member connected to the brakemember for rotation therewith and for axialmover'nent thereon, anannular friction ring secured to each face of thedisc member forrotation therewith,

an annular cylinder member secured to the "support on one side of thedisc, a rigid piston having substantially the same area as each of thefriction rings slidably and nonrot'atably mounted in the cylinderandrhaving inner. and

' outer wall portions connected by'a partition, said piston and'cylinderforming a pressure chamber therebetween and said partition forming anouter wall for said chamber; an annular channel'in the outer end of saidpiston adjacent one of the friction rings on said brake disc member,said partition forming a back wall of said channel, an annular metalfriction element secured along its inner and outer peripheral portionstothe outer end of the piston and forming an outer end Wall for saidchannel, said periphto, an annular cylinder mounted on the supporthavingan.

eral portions bounding an annular outer friction surface on said elementadapted to engage said one friction ring and having substantially thesame-area as the ring, sub-.

boundingan annular'outer friction surface'on the second element havingan area substantially the same as that'of the other of sa'id frictionrings'and adapted to engage' 'said other friction ring, substantiallythe entire inner surface 7 of said second friction element directlyopposite said Y annular friction surface thereof being'exposed ,in-thechannel in said element supporting member, inlet and outletconnectionsto said channels in said piston and fric: tionelement supporting member,.said connections and channels forming a circuit for the circulation ofcooling liquid in said channels in direct engagement with said exposedinner surfaces of said friction elements, and a con- 'nection -betweensaid circuit and pressure chamber for subjecting said piston to thepressure of liquid in said circuitlj I "2.':Liquid cooled and liquidpressure operated brake mechanismasi set .forth in claim '1, whereinenlarged ,cha rnbersare provided in said inletand outlet connections,each plenum chamber having'a pair of separate passages connected theretoand connected respectively to said piston channel sand to theiQchannel'inisaid friction element supporting member. 7 I

3; Liquidcooled and liquid pressure'operated brake mechanism as set"forth in claim' .1 including cooling liquid supplyingmeans havingconnection with said inlet and outlet connections, said liquid supplyingmeansincluding means for circulating cooling liquid through saidcircuit, means for controlling the flow of liquid through said circuit,and means for controlling the pressure of the liquid in said circuit. VV V 4(Liquid cooled and liquid pressure operated brake mechanism as setforth in claim 1, wherein the open ends of said piston and said frictionelement supporting member channels have substantially the same area assaid piston and are in substantial alignment with the respectiveadjacent friction rings, 7

5. Liquid cooled and liquid pressure operated brake mechanism as setforth in claim 1, wherein thecylinder is provided with piston sealingand retracting means comprising grooves in the inner and outer walls ofthe cylinder and resilient sealing rings of rubber-like materialpositioned in said grooves under compression between the bottoms of thegrooves and the adjacent surfaces of the piston and in slidingfrictional engagement with the latter, said sealing rings beingsubjected to' the pressure of liquid in said chamber and being operable'on release of pressure from said pressure chamber 'to retract thepiston and disengage the metal friction, element thereon from theadjacent friction ring, and means are provided for retracting the brakedisc member on retraction'of said piston,

- said last named-means including resilient retracting means ofrubber-like material interposed under compression between said brakedisc member and said rotatable brake member for resilientlyopposing-axial movement of said the rotatable brake member to effect abrake application,

a connection for supplying fluid pressure to said cylinder;

"an annular friction element secured to said support onthe other side ofthe. disc member and engageable by the latter on said axial movementthereof by said piston, and means for automatically retracting said'piston and disc member to release positions on release of the brake andto adjust said release positions in accordance witii'wear of. saidpiston friction facefportion, disc member and friction element, saidmeans including resilient sealing rings of rubber-like'materialpositioned in grooves associated with the cylinder walls .undercomprmsion between the bottoms of said grooves and the adjacentpistomwalls and in sliding frictional engagement withjsaid walls, saidsealing rings being subjected. at all times to the pressure in saidcylinder, and resilient means of rubber-like material positioned undercompression between said rotatable brake member and said disc member,said resilient means being'in sliding frictional engagement with one ofsaid members and connected for movement 'bodily with the a other of saidmembers, said piston sealing rings and said resilient'means beingrespectively so dimensionedand constituted as to distort without slidingalong said pistonwalls' and along said one member when the piston anddisc member are moved predetermined distanceson movement 13 of thepiston to eifect a brake application, and to respectively slide alongsaid piston walls and along said one member when said piston and saidone member move greater distances.

7. The combination as set forth in claim 6, wherein the resilient pistonsealing rings are so dimensioned and arranged with respect to saidresilient means as to insure that said predetermined distance saidpiston sealing rings may distort without sliding is greater than thepredetermined distance said resilient means may distort without sliding.

8. Liquid cooled and fiuid pressure operated brake mechanism including asupport, a brake member mounted for rotation on the support, a brakedisc member connected to the brake member for rotation therewith andaxial movement therealong and having an annular friction ring portion oneither side thereof, an annular cylinder secured to the support on oneside of the disc, a rigid annular piston slidably and nonrotatablymounted in the cylinder having substantially the same area as each ofsaid brake disc annular ring portions and having inner and outer wallportions connected by a partition, said piston and cylinder forming apressure chamber therebetween and said partition forming an outer Wallof said chamber, an annular channel in the outer end of said pistonadjacent one of the friction ring portions on said brake disc member,said partition forming a back wall for said channel, an annular metalfriction element secured along its inner and outer peripheral portionsto the outer end of said piston and forming an outer end wall for saidchannel, said peripheral portions bounding an annular outer frictionsurface area on said element adapted to engage said one friction ringportion and having substantially the same area as said one friction ringportion, substantially the entire inner surface of said element directlyopposite said annular friction surface portion being exposed in saidchannel, an annular friction element supporting member secured to saidsupport having an annular channel formed therein having an open endadjacent the other of said annular friction ring portions, a secondannular metal friction element secured along its inner and outerperipheral portions to said supporting member, said peripheral portionsbounding an annular outer friction surface area on said second elementhaving an area substantially the same as that of the other of saidannular friction ring portions and adapted for engagement therewith,substantially the entire inner surface of said second friction elementdirectly opposite said annular friction surface thereon being exposed inthe channel in said element supporting member, inlet and outletconnections to the channels in said piston and in said friction elementsupporting member, said connections and channels forming a circuit forthe circulation of cooling liquid therethrough in direct engagement withthe inner surfaces of said friction elements exposed in said channels,and means including a connection for supplying fluid under pressure tosaid pressure chamber at a pressure substantially the same as thepressure in said circuit to actuate said piston to eifect engagement ofsaid metal friction elements with said friction ring portions of saidbrake disc member.

9. Liquid cooled and fluid pressure operated brake mechanism including asupport, a brake member mounted for rotation on the support, a brakedisc member connected to the brake member for rotation therewith andaxial movement therealong and having an annular friction ring portion oneither side thereof, an annular cylinder secured to the support on oneside of the disc, a rigid annular piston slidably and non-rotatablymounted in the cylinder having substantially the same area as each ofsaid brake disc annular ring portions and having inner and outer wallportions connected by a partition, said piston and cylinder forming apressure chamber therebetween and said partition forming an outer wallof said chamber, an annular channel'inthe outer end earnest;

l4 of said piston adjacent one of the friction ring portions on saidbrake disc member, said partition forming a back wall for said channel,an annular metal friction element secured along its inner and outerperipheral portions to the outer end of said piston and forming an outerend wall for said channel, said peripheral portions bounding an annularouter friction surface area on said element adapted to engage said onefriction ring portion and having substantially the same area as said onefriction ring portion, substantially the entire inner surface of saidelement directly opposite said annular friction surface portion beingexposed in said channel, an annular friction element supporting membersecured to said support having an annular channel formed therein havingan open end adjacent the other of said annular friction ring portions, asecond annular metal friction element secured along its inner and outerperipheral portions to said supporting member, said peripheral portionsbounding an annular outer friction surface area on said second elementhaving an area substantially the same as that of the other of saidannular friction ring portions and adapted for engagement therewith,substantially the entire inner surface of said second friction elementdirectly opposite said annular friction surface thereon being exposed inthe channel in said element supporting member, inlet and outletconnections to the channels in said piston and in 'said friction elementsupporting member, said connections and channels forming'a circuit forthe circulation of cooling liquid therethrough in direct engagement withthe inner surfaces of said friction elements exposed saidchannels, aconnection for supplying fluid under pressure to said pressure chamberto actuate said piston to eflfect engage ment of said metal frictionelements with said friction ring portions of said brake disc member, andcontrol means having connections with said inlet and outlet connectionsand said pressure chamber connection, said control means including meansfor circulating a cooling liquid through said circuit, means forcontrolling the flow of liquid therethrough, means for controlling thepressure of liquid in said circuits, and means for maintaining a fluidpressure in said pressure chamber substantially the same as, thepressure in said circuit.

10. Liquid cooled and liquid pressure operated brake mechanism includinga support, a brake member mounted for rotation on the support, a brakedisc member connected to the brake member for rotation therewith andaxial movement therealong, an annular friction ring secured to each faceof the disc member for rotation therewith, an annular cylinder securedto the support on one side of the disc, a rigid annular piston slidablyand non-rotatably mounted in the cylinder having substantially the samearea as each of said friction rings and having inner and outer Wallportions connected by a partition, said piston and cylinder forming apressure chamber therebetween and said partition forming an outer Wallof said chamber, an annular channel in the outer end of said pistonadjacent one of said friction rings, said partition forming a back wallfor said channel, an annular metal friction element secured along itsinner and outer peripheral portions to the outer end of said piston andforming an outer end wall for said channel, said peripheral portionsbounding an annular outer friction surface on said element adapted toengage said one friction ring and having substantially the same area assaid one ring, substantially the entire inner surface of said elementdirectly opposite said annular friction surface portion being exposed insaid channel, an annular friction element supporting member secured tosaid support having an annular channel formed therein having'its openend adjacent the other of said friction rings, a second annular metalfriction element secured along its inner and outer peripheral portionsto said supporting member, said peripheral portions bounding an annularouter friction surface on said second element having an areasubstantially the same'as that of the other of "said friction 1'5 7 ringsand adapted for engagement therewith, substantially the entire innersurface of said second element directly plenum chambers; connectionsfrom one ofthe plenum chambers leading respectively to the channel insaid friction element supporting memberadjacent one side of said damtherein and'to said pressure chamber, a connection, from said pressurechamber to said piston channel, connections from the other of saidplenum chambers V respectively to said channel in said friction elementsupporting member adjacent the other side of'said dam and to said pistonchannel at a point approximately 180 from said connection to saidpressure chamber, and inlet and outlet ports for supplying coolingliquid to said brake mechanism and for discharging cooling liquidtherefrom, one of said ports having a connection with one of said plenumchambers and the other of said ports having a connection with the otherof said plenum chambers.

l1.- Liquid cooled and liquid pressure operated brake mechanismincluding a support, a brake member mounted for rotation on saidsupport, a pair of brakediscs mounted on said brake member forrotationitherewith and axial' movement therealong, annular frictionrings secured to the opposite surfaces of each of said brake discs,annular cylinders-secured to said support, said cylinders being mountedrespectively adjacent one side'of one of said discs andadjacent theopposite side of the other of said discs, rigid pistons each havingsubstantially the same area as each of said friction rings slidably andnon-rotatably mounted in said cylinders and having inner and outer wallportions connected by partitions, said cylinders and pistons formingpressure chambers therebetween and said s mechanism including a support,a brake member mounted for rotationzon the support, a plurality of brakediscs secured to the brake member for'rotation therewith and axialmovement therealong, friction rings secured to each side of each of saiddiscs, annular cylinderssecured to the support'and positioned on oneside of each of said discs, each cylinder having a rigid piston slidablyand non-rotatably mounted therein, each piston having subt, stantiallythe same area as each of the friction rings on the adjacent disc, saidpistons having inner and outer Wall portions and a partition connectingsaid wall portions, said pistons and cylinders forming pressure chamberstherebetween and said partitions forming outer walls for said chambers,annular channels in the outer end of each piston, said partitionsforming back walls for the channels, annular metal friction elementssecured along their inner and outer peripheral portions tothe outer endsof said pistons, said peripheral portions bounding annular outerfriction surface portions on said elements adapted totengage theadjacent friction rings on the discs and having'substantially the sameareas as said adjacent friction rings, friction element supportingmembers secured to said support, one of said element supporting membersbeing positioned adjacent each'disc on the'side opposite the cylinderpositioned adjacent said one side of supporting member adjacent'saidopposite side of'said adjacent tdisc, annular metal friction elementssecured partitions forming outer walls of said chambers, an an-j nularchannel in the outer end of each piston adjacent the friction ring onsaid one side of the adjacent disc,

- said partitions forming back walls for said channels,

annular metal friction elements secured along their'inner and outerperipheral portions to the outer ends of said pistons and forming outerend walls for the channels therein, said peripheral portions boundingannular outer friction surface portions on said elements adapted toengage the adjacent friction rings and having substantially the samearea as the adjacent rings, substantially the entire inner surfaces ofsaid elements directly opposite ing their open ends adjacent theremaining friction rings' on said discs, annular metal friction elementssecured along the inner and outer peripheral portions thereof tortheopposite sides'of said element supporting 1 member and forming end wallsfor said channels, said peripheral portions bounding annular outerfriction sur- 7 face portions 611 the last named elements having areas"substantially the same as'thos'e of the adjacent friction rings'andadapted for engagement by'siaid rings, substantiallylthe entire'inner'surface portions ofsaid elements directly opposite saidouter frictionsurface portions be'lngrexposed in the corresponding channels in saidelement supporting member, inletand outlet connections to said'channelsin said pistons and in said element'supporting member, said connectionsand channels forming a circuit for the circulation of cooling liquid insaid channels-in direct engagement'with the exposed inner surfaces ofall said'metalfrictionelements, and means for con;

necting said circuit and pressure chambers for subjecting said pistonsto the pressure of liquid in said circuit. I 7, 1 2. Liquid cooled andliquid pressureoperatedfbralre along their inner and outer peripheral,portions to the friction element supporting members, a metal frictionelement for closing the end of each ofrthe channels in the frictionelement supporting members, said peripheral portions of said elementsbounding outer friction surface portions having substantially the sameareas as the pistons on the opposite sides of the adjacent discs andsubstantially the same areas as the friction rings on said adjacentdiscs, substantially the entire inner surfaces of each friction elementdirectlyopposite said outer annular friction surface portion thereof'being'exposed in the corresponding channel, inlet and outletconnections to said piston and element supporting member channels, saidconnections and channels forming a circuit for the circulation ofcooling liquid through said channels in intimate engagement with saidexposed inner surfacestof said metal friction elements,tand means forconnecting saidtcircuit and pressure chambers for subjecting saidpistons to the pressure of liquid in saidcircuit;

13. Liquid cooled and liquid pressure operated brake mechanism as setforth in claim 12, wherein liquid cooling and liquid supplying'me ansare provided having con.- nections with said inlet and outlet ports,said liquid supplying means including means for circulating coolingliquid through saidfcireuit upon actuation of the brake, -means forcontrolling the flow of liquid through said plurality of annularcylinders mountedonjthe support,

a one of saidcylinders being mounted on one side of each of said discmembernannular pistons Islidably and. lion- 7 rotatably: mounted inthecylinders having friction face portions at their outer ends adapted.to engage and move an adjacent disc member axially during a brakeapplication, a connection for supplyingfluidundenpressure to saidcylinders,fa plurality of stationary annular friction 'shoes'securedtotthe supported the other: sides of said disc members and engageable bythe latter on axial movement thereof ;by said-pistons, and meansforautomatrcally retracting said pistons and disc members toreleasepositions on release ofthe' brake and for automatically; adjusting said release positions in accordance withwearof saidpistonjaeefortions, disc; members and shoes, sa d means includingresilient sealing rings of rubber-like material positioned in groovesassociated with the cylinder walls under compression between the bottomsof said grooves and said pistons and in sliding frictional engagementwith said pistons, said rings being subjected at all times to thepressure in said cylinders, and resilient means of rubber-like materialinterposed under compression between said rotatable bralse member andeach disc member in sliding frictional engagement with one of themembers and connected for movement bodily with the other of saidmembers, said sealing rings and resilient means being respectively sodimensioned and constituted as to distort Without sliding along saidpiston walls and along one of the members when the pistons and discmembers are moved predetermined distances on movement of the pistons toeffect a brake application, and to respectively slide along said pistonsand said one member when said pistons and disc members move greaterdistances.

15. In a disc brake mechanism having a support, a brake member rotatablymounted on the support, a brake disc member connected to the rotatablebrake member for rotation therewith and axial movement with respectthereto, a cylinder mounted on the support, a friction element mountedfor axial movement on the support having a friction surface adapted forengagement with one side of said disc member, means for preventingrotation of said friction element on the support, a piston slidablymounted in said cylinder for moving the friction element to effectengagement of said friction surface with said one side of the discmember and to move the disc member axially of the rotatable brake memberto effect a brake application, a connection for supplying fluid underpressure to the cylinder, a friction element secured to the support onthe other side of said disc member and engageable by the latter on saidaxial movement thereof by said piston, and means for automaticallyretracting said piston and disc member to release positions on releaseof the brake and for adjusting said release positions in accordance withwear of the friction elements and disc member, said means including agroove in the wall of said cylinder having a resilient sealing ring ofrubberlike material positioned in the groove under compression betweenthe bottom of the groove and the adjacent surface of the piston and insliding frictional engagement with the latter, said sealing ring beingsubjected at all times to the pressure of fluid in said cylinder, andresilient means of rubber-like material positioned under compressionbetween said rotatable member and said disc member, said resilient meansbeing in sliding frictional engagement with one of said members andconnected for movement bodily with the other of said members.

16. Liquid cooled disc brake mechanism including a support, a brake shoemounted for axial movement on the support, a stationary brake shoemounted on the support, each shoe having an annular channel for coolingliquid and annular metal friction elements closing said channels withtheir inner surfaces exposed in said channels and their outer surfacesbeing friction surfaces in spaced apart face to face relationship, anannular brake disc mounted on the support for rotation between saidelement outer surfaces and for axial movement relative to the support,the peripheral portions of said elements being secured to said shoeswith the outer surface portions bounded by said peripheral portionsbeingengageable with said disc and the inner surfaces thereof inalignment with said outer surface portions being exposed in saidchannels, means for circulating cooling liquid under pressure throughsaid channels, fluid pressure responsive means for actuating said firstnamed shoe to effect engagement of the friction element thereof withsaid disc and to move the disc to effect engagement thereof with thefriction element on the stationary shoe, and means for supplying fluidunder pressure to said fluid pressure responsive means, said coolingliquid circulating means and said fluid pressure supplying means beingso constituted that the actuating force exerted by said pressureresponsive means on said first named shoe is maintained substantiallyequal to the total force exerted by the pressure of the cooling liquidon each of said inner surfaces of said friction elements exposed in saidchannels and in alignment with said outer surface portions of saidelemcnts, whereby the forces exerted in one direction on said innersurfaces of said metal friction elements exposed in said channels aresubstantially balanced by the forces acting in the opposite direction onsaid outer surface portions of said elements due to engagement of saidouter surface portions with said disc.

References Cited in the file of this patent UNITED STATES PATENTS1,972,353 North et a1 Sept. 4, 1934 2,051,286 Boykin Aug. 18, 19362,152,489 Lamb Mar. 28, 1939 2,406,304 Levy Aug. 20, 1946 2,471,858Bloomfield May 31, 1949 2,664,176 Whalen Dec. 29, 1953 2,710,078Cardwell June 7, 1955 2,747,702 Van Zehn May 29, 1956 FOREIGN PATENTS980,742 France Jan. 3, 1951 1,123,407 France June 1 1, 1956 477,510Great Britain Dec. 31, 1937 701,725 Great Britain Dec. 20, 1953 739,244Great Britain Oct. 26, 1955

